Hello Luis,
The two resources that I use to understand CERES source code are
"Understanding options for agricultural production" (G.Y. Tsuji, G.
Hoogenboom, and P.K. Thornton eds.) and the old "CERES-Maize: a simulation
model of maize growth and development" (C.A. Jones and J.R. Kiniry eds.,
1986, Texas A&M University Press, College Station, USA). In the back of the
second book is a glossary of the variable names for CERES-Maize source
code. CERES-Rice uses many, but not all, of the same variable names as
CERES-Maize.
Based on these resources, and some of my own understanding, this is my
interpretation of the source code you mention below.
1. MPLAG is the leaf area growth (cm^2/plant) for the current day.
2. A is probably a factor that regulates the size of a single leaf (cm^2).
3. CUMPH is the cumulative number of fully expanded leaves.
4. XTN is probably another factor that regulates the size of a single leaf.
5. TI is the fraction of a single leaf emerging in the current day.
6. PHINT is the phyllochron interval.
7. PC is a factor that gradually lengthens the phyllochron interval for the
first five leaves.
The quantities important to calculate MPLAG are
[A/CUMPH*(-BF)*XTN*EXP(XTN)], [TI], [TSHOCK], and
[AMIN1(TURFAC,TEMF,AGEFAC)]. The quantity [A/CUMPH*(-BF)*XTN*EXP(XTN)] is
probably the area of the single leaf numbered CUMPH (note: if you plot
[A/CUMPH*(-BF)*XTN*EXP(XTN)] against CUMPH you can see the curve that
describes how single leaf area varies with leaf number) . TI is the
fraction of leaf emerged in the current day, so
[A/CUMPH*(-BF)*XTN*EXP(XTN)] * [TI] is the leaf area growth for the current
day. [TSHOCK] and [AMIN1(TURFAC, TEMF, AGEFAC)] are stress factors that
reduce the leaf area growth in the current day.
My understanding of the code may not be correct, so if any one else
knows better please let Luis know. Thank you.
Sincerely,
Richard
At 10:41 AM 05/16/2003 -0700, Luis Alvarez wrote:
> In CERES-rice, at ISTAGE = 1, it is calculated the daily growth of leaf
area per plant: MPLAG = A / CUMPH * (-BF) * XTN * EXP(XTN) * TI * TSHOCK *
AMIN1(TURFAC, TEMF, AGEFAC).
>I donīt know the meaning of some of these factors and cannot find them at
the world related bibliography. Could somebody help me to solve this
problem?. What is A?, a constant = 3800?, CUMPH is the number of fully
expanded leaves?. Is BF previous day leaf weight? (BF=0,12).
XTN=-9,678*EXP(-BF+CUMPH). XTN?. TI=DTT/(PHINT*PC), TI=leaf fraction
emerging in one day?. PHINT=83šC.day.leaf-1, phyllochron.
>PC=0,66+0,068*CUMPH.
>Where at the literature could I get the meaning of variables that compose
CERES-rice?.
>During three rice crop cycles I collected field information to validate
CERES-rice and to adequate it to our conditions must know how it was built.
As an example I cannot match the measured grains per panicle with the
simulated values, how can I find a solution if I donīt know the meaning of
some variables that determine it?.
>Sincerely yours:
>Luis E. Alvarez L.
>Universidad Ezequiel Zamora. UNELLEZ.
>Guanare. Estado Portuguesa.
>Venezuela
>
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